“Not just my father,” Isherwood said. “I’ve seen it, too. Vincent painted it in Auvers, during the final days of his life. There’s a rumor it might have been his undoing. The problem is, the painting isn’t for sale, and it probably never will be. The family has made it clear to me they’ll never part with it. They’re also bound and determined to keep its very existence a secret.”

“Tell me the story again.”

“I don’t have time now, Gabriel. I have a ten-thirty appointment at the gallery.”

“Cancel your appointment, Julian. Tell me about that painting.”

ISHERWOOD CROSSED the footbridge over the lake and headed toward his gallery in St. James’s. Gabriel shoved his hands a little deeper into his coat pockets and followed after him.

“Ever cleaned him?” Isherwood asked.

“Vincent? Never.”

“How much do you know about his final days?”

“About what everyone knows, I suppose.”

“Bollocks, Gabriel. Don’t try to play the fool with me. Your brain is like the Grove Dictionary of Art.”

“It was the summer of 1890, wasn’t it?”

Isherwood gave a professorial nod of his head. “Please continue.”

“After Vincent left the asylum in Saint-Rémy, he came to Paris to see Theo and Johanna. He visited several galleries and exhibits, and stopped at Père Tanguy’s artists’ supply store to check on some canvases he had in storage there. After three days he began to get restless, so he boarded a train for Auvers-sur-Oise, about twenty miles outside Paris. He thought Auvers would be ideal, a quiet country setting for his work but still close to Theo, his financial and emotional lifeline. He took a room above Café Ravoux and placed himself in the care of Dr. Paul Gachet.”

Gabriel took Isherwood’s arm and together they darted through an opening in the traffic on the Mall and entered the Marlborough Road.

“He started painting immediately. His style, like his mood, was calmer and more subdued. The agitation and violence that characterized much of his work at Saint-Rémy and Arles was gone. He was also incredibly prolific. In the two months Vincent stayed in Auvers he produced more than eighty paintings. A painting a day. Some days two.”

They turned into King Street. Gabriel stopped suddenly. Ahead of them, waddling along the pavement toward the entrance of Christie’s auction house, was Oliver Dimbleby. Isherwood turned suddenly into Bury Street and picked up where Gabriel had left off.

“When Vincent wasn’t at his easel, he could usually be found in his room above Café Ravoux or at the home of Gachet. Gachet was a widower with two children, a boy of fifteen and a daughter who turned twenty-one during Vincent’s stay in Auvers.”

“Marguerite.”

Isherwood nodded. “She was a pretty girl and she was also deeply infatuated with Vincent. She agreed to pose for him-unfortunately with out her father’s permission. He painted her in the garden of the family home, dressed in a white gown.”

“Marguerite Gachet in the Garden,” Gabriel said.

“And when her father found out, he was furious.”

“But she posed for him again.”

“Correct,” Isherwood said. “The second painting is Marguerite Gachet at the Piano. She also appears in Undergrowth with Two Figures, a deeply symbolic work that some art historians saw as a prophecy of Vincent’s own death. But I believe it’s Vincent and Marguerite walking down the aisle-Vincent’s premonition of marriage.”

“But there was a fourth painting of Marguerite?”

“Marguerite Gachet at Her Dressing Table,” said Isherwood. “It’s the best of the lot by far. Only a handful of people have ever seen it or even know it exists. Vincent painted it a few days before his death. And then it disappeared.”

THEY WALKED TO Duke Street, then slipped through a narrow passageway, into a brick quadrangle called Mason’s Yard. Isherwood’s gallery occupied an old Victorian warehouse in the far corner, wedged between the offices of a minor Greek shipping company and a pub that was inevitably filled with pretty office girls who rode motor scooters. Isherwood started across the yard toward the gallery, but Gabriel snared his lapel and pulled him in the opposite direction. As they strolled the perimeter through the cold shadows, Isherwood talked of Vincent’s death.

“On the evening of July 27, Vincent returned to Café Ravoux in obvious pain and struggled up the stairs to his room. Madame Ravoux followed after him and discovered he’d been shot. She sent for a doctor. The doctor, of course, was Gachet himself. He decided to leave the bullet in Vincent’s abdomen and summoned Theo to Auvers. When Theo arrived the following morning, he found Vincent sitting up in bed smoking his pipe. He died later that day.”

They came into a patch of brilliant sunshine. Isherwood shaded his eyes with his long hand.

“There are many unanswered questions about Vincent’s suicide. It’s not clear where he got the gun or the precise place where he shot himself. There are questions, too, about his motivation. Was his suicide the culmination of his long struggle with madness? Was he distraught over a letter he’d just received from Theo suggesting that Theo could no longer afford to support Vincent along with his own wife and child? Did Vincent take his own life as part of a plan to make his work relevant and commercially viable? I’ve never been satisfied with any of those theories. I believe it has to do with Gachet. More to the point, with Dr. Gachet’s daughter.”

They slipped into the shadows of the yard once more. Isherwood lowered his hand.

“The day before Vincent shot himself, he came to Gachet’s house. The two quarreled violently, and Vincent threatened Gachet with a gun. What was the reason for the argument? Gachet later claimed that it had something to do with a picture frame, of all things. I believe it was over Marguerite. I think it’s possible it had something to do with Marguerite Gachet at Her Dressing Table. It’s an exquisite work, one of Vincent’s better portraits. The pose and the setting are clearly representative of a bride on her wedding night. Its significance would not have been lost on a man like Paul Gachet. If he’d seen the painting-and there’s no reason to believe he didn’t-he would have been incensed. Perhaps Gachet told Vincent that marriage to his daughter was out of the question. Perhaps he forbade Vincent ever to paint Marguerite again. Perhaps he forbade Vincent ever to see Marguerite again. What we do know is that Marguerite Gachet wasn’t present at Vincent’s funeral, though she was spotted the next day tearfully placing sunflowers on his grave. She never married, and lived as something of a recluse in Auvers until her death in 1949.”

They passed the entrance to Isherwood’s gallery and kept walking.

“After Vincent’s death his paintings became the property of Theo. He arranged for a shipment of the works Vincent had produced at Auvers and stored them at Père Tanguy’s in Paris. Theo, of course, died not long after Vincent, and the paintings became the property of Johanna. None of Vincent’s other relatives wanted any of his work. Johanna’s brother thought them worthless and suggested they be burned.” Isherwood stopped walking. “Can you imagine?” He propelled himself forward again with a long stride. “Johanna catalogued the inventory and worked tirelessly to establish Vincent’s reputation. It’s because of Johanna that Vincent van Gogh is regarded as a great artist. But there’s a glaring omission in her list of Vincent’s known works.”

“Marguerite Gachet at Her Dressing Table.”

“Precisely,” said Isherwood. “Was it an accident or intentional? We’ll never know, of course, but I have a theory. I believe Johanna knew that the painting may have contributed to Vincent’s death. Whatever the case, it was sold for a song from the storeroom at Père Tanguy’s within a year or so of Vincent’s death and never seen again. Which is where my father enters the story.”